摘要
目的:通过数字化X线牙片和体视显微镜测量根管锥度,获得下颌第一前磨牙根管的初始锥度,为根管器械材料的锥度设计和临床正确选择锥度器械提供参考。方法:应用数字化X线牙片机,采用平行投照技术,分别从颊舌向和近远中向对23个13~23岁下颌第一前磨牙(单根管)根管进行摄片,通过相应图像分析软件对根管冠、中、根尖各段的管径及长度进行测量;然后通过制样机对同组样本1mm等距离磨除,利用体视显微镜对断面根管管径进行摄片及测量。分析整理数据,通过相应数学公式计算各组根管锥度。结果:通过X线片得到根管近中远中向锥度分别为0.03、0.07、0.09;颊舌向分别为0.09、0.24、0.19。体视镜得到近中远中向锥度0.07、0.06、0.07;颊舌向为0.15、0.24、0.17。两种方法所得对应结果经t检验均无显著性差别,(P〉0.05)。结论:①13—23岁下颌第一前磨牙根尖1/3段的锥度近中远中向为0.07~0.09,颊舌向为0.17~0.19,对于该年龄段根管,0.07—0.09锥度器械较适合;②数字化X线牙片平行投照可准确得到该牙根管的锥度;③该组牙颊舌向根管的中1/3段锥度明显大于冠1/3段,根管预备中可导致根管冠1/3段(尤其是根管口)颊舌侧壁的过度切割。
AIM: To determine the root canal initial taper of mandibular first premolars by use of digital X - ray system and stereomicroscope, which can contributed to design the shape of preparation instruments and select the instrument's taper during root canal therapy. METHODS: 23 extracted single root untreated human mandibular first premolars (mean age = 18; range 13 223 years) were selected. Each tooth was radiographed by digital X- ray system. Diameters of cervical, middle, and apical third of the canals were measured with a imaging software. Then the teeth were embedded in resin. With help of sample preparation equipment, the resins were robbed off in a thickness of 1 mm perpendicular to the long axis of the tooth. For each cross section, bucco - lingual and mesio - distal diameters of the canal were measured under stereomicroscope. Finally the taper were calculated and analyzed. RESULTS: By use of digital X - ray system , the average taper of cervical, middle, and apical third of these root canals were : 0.09,0.24, 0.19 bucco - lingually and 0. 03,0. 07 ,0. 09 mesio - distally. Under stereomicroscope the taper were 0.15 ,0. 24 ,0.17 and 0. 07,0. 06,0. 07 respectively. NO difference was observed between two measurement methods about the canal taper by t - test( P 〉 0.05 ). CONCLUSION : (1) The results showed that the taper of the apical third were 0.17 - 0.19 for the bucco - lingual : and 0.07 - 0.09 for mesio - dista. Obviously the taper of instruments between 0.07 - 0.09 is suitable for preparing the mandibular first premolar at the age of 13 - 23. (2) By digital X - ray system with parallel project, we can obtain the canal's taper precisely . (3)The largest taper instruments may increase the reduction of root structure ( especially at lingual and buccal canal wall), because the original bucco - lingual diameter of these root canal orifice is smaller than the diameter of middle area of cervical third .
出处
《牙体牙髓牙周病学杂志》
CAS
2008年第8期429-433,共5页
Chinese Journal of Conservative Dentistry